Localization of telomerase activity to a doublet. (A) Analysis of Triton X-100 eluate of anti-Ro60 immunoprecipitates. Analysis was performed on an 8% native PAGE gel. Immunoprecipitates from 1 mg of lysates from SW-480 cells were either untreated (−), RNase A-treated (+ RN) or proteinase K-treated (+ PK) and detected by silver staining. Arrow indicates position of doublet. (B) Doublet peaks for hTR expression. RNA was extracted from the gel slices (0.5 cm) from the native gel and analyzed by RT-PCR for hTR expression. POS, positive control; NEG, template minus control. (C) Lack of Ro60-Associated hY3 RNA in the Doublet. RNAs from doublet excised from three different gel slices were analyzed by RT-PCR for hTR, hY3, and GAPDH expression. POS, positive control; NEG, negative control. (D) Telomerase activity comigrates with the doublet. A gel slice containing the doublet was analyzed for telomerase activity in the absence (−) or presence (+) of RNase A pretreatment.